Americans renouncing U.S. citizenship surged sixfold in the second quarter from a year earlier as the government prepares to introduce tougher asset-disclosure rules.

Expatriates giving up their nationality at U.S. embassies climbed to 1,131 in the three months through June from 189 in the year-earlier period, according to Federal Register figures published today. That brought the first-half total to 1,810 compared with 235 for the whole of 2008.

The U.S., the only nation in the Organization for Economic Cooperation and Development that taxes citizens wherever they reside, is searching for tax cheats in offshore centers, including Switzerland, as the government tries to curb the budget deficit. Shunned by Swiss and German banks and facing tougher asset-disclosure rules under the Foreign Account Tax Compliance Act, more of the estimated 6 million Americans living overseas are weighing the cost of holding a U.S. passport.

“With the looming deadline for Fatca, more and more U.S. citizens are becoming aware that they have U.S. tax reporting obligations,” said Matthew Ledvina, a U.S. tax lawyer at Anaford AG in Zurich. “Once aware, they decide to renounce their U.S. citizenship.”

Fatca requires foreign financial institutions to report to the Internal Revenue Service information about financial accounts held by U.S. taxpayers, or held by foreign entities in which U.S. taxpayers hold a substantial ownership interest. It was estimated to generate $8.7 billion over 10 years, according to the congressional Joint Committee on Taxation.

The 2010 Fatca law requires banks to withhold 30 percent from “certain U.S.-connected payments” to some accounts of American clients who don’t disclose enough information to the IRS. While banks can sign agreements to report to the IRS individually, many are precluded from doing so by privacy laws in their jurisdictions.

The Treasury Department last month announced that the IRS will delay the start of Fatca by six months until July 1, 2014, to give foreign banks time to comply with the law. The extension of the act follows a previous one-year delay announced in 2011.

Financial institutions including Canada’s Toronto-Dominion Bank (TD) and Allianz SE of Germany have expressed concerns that Fatca is too complex.

The latest delay comes after the Swiss government agreed in February to simplifications that will help the country’s banks implement Fatca.

“The United States wishes to ensure that all income earned worldwide by U.S. taxpayers on accounts held abroad can be taxed by the United States,” the Swiss government said on April 10.

Since 2011, Americans, who disclose their non-U.S. bank accounts to the IRS, must file the more expansive 8938 form that asks for all foreign financial assets, including insurance contracts, loans and shareholdings in non-UNN.S. companies.

Failure to file the 8938 form can result in a fine of as much as $50,000. Clients can also be penalized half the amount in an undeclared foreign bank account under the Banks Secrecy Act of 1970.

The implementation of Fatca from July next year comes after UBS, Switzerland’s largest bank, paid a $780 million penalty in 2009 and handed over data on about 4,700 accounts to settle a tax-evasion dispute with the U.S. Whistle-blower Bradley Birkenfeld was sentenced to 40 months in a U.S. prison in 2009 after informing the government and Senate about his American clients at the Geneva branch of Zurich-based UBS AG.

The additional compliance costs for companies to ensure that Americans they hire are filing the correct U.S. tax returns and asset-declaration forms are at least $5,000 per person, said Ledvina.

For individuals, the costs are also rising. Getting a mortgage or acquiring life insurance is becoming almost impossible for American citizens living overseas, Ledvina said.

“With increased U.S. tax reporting, U.S. accounting costs alone are around $2,000 per year for a U.S. citizen residing abroad,” the tax lawyer said. “Adding factors, such as difficulty in finding a bank to accept a U.S. citizen as a client, it is difficult to justify keeping the U.S. citizenship for those who reside permanently abroad.“